This invention relates generally to the field of methods and apparatus for pitting fruits of the drupe type. More particularly, it relates to apparatus for selectively torque pitting such fruits having sound pits and for automatically and selectively spoon pitting such fruit having split pits, irrespective of the order in which fruit having sound pits and fruit having split pits are presented to the pitting station.
The most common method and apparatus used in pitting fruits of the drupe type, such as peaches, apricots and the like, provide for torque pitting the fruit. In this technique the fruit body halves are substantially bisected and the pit is gripped against rotation while the fruit body halves are rotated relative to and about an axis extending through the pit, thus twisting the fruit body halves free of the pit. However, it is not uncommon for some of the fruit presented to the pitting station to have unsound or split pits, these fruits being intermingled with other such fruit having sound pits. If the torque pitting technique is used with fruit having a split pit, generally all that is accomplished is the bisecting of the fruit and its split pit into two halves and then passing the fruit body halves with their attached pit halves onto subsequent stations where these fruit body halves must be repitted with a coring spoon to remove the split pit halves.
One seemingly obvious solution to the problem is use a spoon pitting machine to cut a core including the split pit from each of the fruits presented, regardless of whether the fruit has a split or sound pit. However, since a spoon pitting machine must necessarily cut a core from each fruit at least as large as the largest pit anticipated, it necessarily removes some of the pulp, or meat, adjacent the pit in order that it may stay clear of the pit itself. This causes a loss of salable fruit pulp from fruit having sound pits, which loss would not occur had torque pitting been used. Various compromise solutions to this problem have been attempted by canners. One such solution has been the provision of separate torque pitting and spoon pitting lines in the canneries with batches of fruits suspected of having a high incidence of split pits being processed along the spoon pitting line and all other fruit being processed along the torque pitting line. This compromise has been unsatisfactory both in its requirement for different sets of torque pitting and spoon pitting equipment, some of which may lie idle if fruit having split pits or sound pits is not available. Additionally, there likely will remain the requirement for spoon pitting the still substantial number of split pit fruit processed along the torque pitting line.
An improvement over the initial compromise may be found by using equipment similar to that disclosed in Brown U.S. Pat. No. 3,829,591 in which a single machine may be configured to operate in a torque pitting mode or, by appropriate modification, to operate in the spoon pitting mode. The apparatus of Brown thus reduces the necessity for separate types of equipment. However, the Brown apparatus operates continuously in the selected one of the two modes, regardless of whether the fruit presented has split or sound pits, until the processing line is shut down and the machine altered to operate continuously in the other mode. Thus, this Brown apparatus may still attempt torque pitting on fruit having split pits or may spoon pit a substantial number of fruit having sound pits, an inefficient procedure in either condition.
A futher advance has been effected by the selective pitting apparatus of Spence U.S. Pat. No. 4,054,675, in which a single pitting apparatus detects the presence of split or sound pits and adjusts the apparatus accordingly. Thus, with the Spence apparatus fruit having sound pits may be torque pitted, to reduce the loss of available fruit pulp, while fruit having split pits would generally be spoon pitted, as required. By the provision of such selective apparatus the unnecessary and wasteful duplication of equipment may be reduced and a substantially higher yield of properly pitted fruit obtained. However, even when the Spence apparatus is in its spoon pitting mode, it requires that the fruit halves be rotated through a full circle relative to a stationary coring knife and about an axis normal to the plane of the fruit suture, a procedure which may both tear the pulp of the fruit and may also cut the core substantially larger than necessary for removal of the pit.